This is set in the future; humans already achieved Type II civilization status. Humans conquered the entire Solar System and managed to colonize Jupiter and all its moons. The next big challenge is to create an artificial living quarter that is bigger than all spacecrafts and planets.
The objective is to leave for the nearest star, as there is an imminent threat as one of the nearby star is going supernova and the gamma ray burst (GRB) is expected to sweep through the entire Solar System. In order to avoid sterilization from the GRB, man decided to leave for a prolonged journey to the next home.
- Spacecraft must not collapse on itself (you are allowed enormous interior space)
- Use all available resource within Solar System.
- Spacecraft must be assembled within heliosphere.
- Transmutation and Magic are not allowed.
- Spacecraft must support all lifeforms within Solar System on its
journey to reach its destination.
- Spacecraft's volume must be bigger than Jupiter.
- Spacecraft must be ready for interstellar travel.
Is it possible for a spacecraft to dwarf Jupiter? How?
Why the need to dwarf Jupiter, you ask? I believe a warp drive isn't available to a Type II civilization, and journeying at subluminal speed to the nearest star would take numerous generations thus more space less conflict.
You only need to consider the feasibility of implementing/erecting an engineering structure on this scale; ignore artificial climates and ecosystems' designs and their influence.